1. Field of the Invention
The present invention relates to the field of wheelchairs. Specifically, this invention relates to a wheeled power attachment that converts a manually powered wheelchair into an electrically powered wheelchair.
2. Description of the Related Art
Manually powered wheelchairs come in a variety of sizes for a variety of purposes. Two of the most common are the standard folding wheelchair and the non-folding rigid frame wheelchair 1 (as seen in FIG. 1) designed for more active and mobile individuals. Manually powered wheelchairs, regardless of the type of frame, generally include a frame 2, seating portion 3, backrest 4, front castor wheels 5, and rear wheels 6 having push rims 7. Each rear wheel 6 has an axle receiver 8 that is aligned with an axle receiver 9 that is connected, directly or indirectly, to the frame 2. A pin 10 locks each rear wheel 6, through its axle receiver 8, to the frame 2 through axle receiver 9. The wheelchairs are powered by the operator gripping the push rims 7 and pushing clockwise or counterclockwise for the specified direction and speed. However, there are some times when manual wheelchairs are not beneficial, such as propelling long distances, managing uneven terrain, or when the user's deficits are of such degree that manual propulsion becomes painful, exhaustive, or relatively impossible given time or circumstances. In these situations, electrically powered wheelchairs are desired to ease the burden and stress on the operator.
Electrically powered wheelchairs have several drawbacks including the expense, size and weight. Financial, storage, and transportation concerns often make it not practical, or possible, for a user to have both an electric powered and manually powered wheelchair. It is especially inconvenient when traveling to take both types of wheel chairs. Additionally, insurance carriers generally will not pay for a user to have both types of chairs.
As a result, there is a need for a wheeled power base attachment that can convert a manual wheelchair into an electric powered wheelchair. While power attachments for manual wheelchairs exist, those in the prior art do not replace the large rear push wheels, are not controlled by a joystick, do not keep the same height as the manual wheelchair, do not support the necessary posture and positioning of the user, and/or do not have an anti-tip/counterbalance mechanism. None of the prior art power attachments provide for connection through the axle receivers of the standard wheelchair. The failure to attach at the axle receiver makes the prior art attachments more difficult to attach to all types of manual wheelchairs as it generally results in a changed center of gravity for the user. Additionally, the failure of the prior art to allow for removal of the rear wheels complicates operation of the electric powered wheelchair by making maneuverability difficult by retaining the cumbersome large rear wheels despite no longer serving a purpose.